1. Field of the Invention
The present invention generally concerns water purification systems, and the packaging of water purification chemicals and chemical systems.
The present invention particularly concerns the purification of water in swimming pools, spas, hot tubs, water storage tanks, wells and water cooling towers, particularly by use of galvanic cells in order to inhibit the growth of bacteria, fungus and algae while significantly reducing the amount of chemicals (chlorine, bromine, hypochlorite, persulfate, ozone, etc.) necessary to maintain water quality.
The present invention still more particularly concerns a synergistic combination of metal ions, as may arise from a galvanic cell, with an oxidizing agent and an algaecide in order to reduce both (i) the required effective amount oxidizing agent and (ii) sensitivity to fluctuations in oxidizing agent concentration, particularly for swimming pools and spas.
The present invention still more particularly concerns a packaging of (i) a galvanic cell producing metal ions, (ii) an oxidizing agent and (iii) an algaecide, particularly for swimming pools and spas.
2. Description of the Previous Art
2.1. Water Purification
One of the main functions of water treatment is to destroy harmful microorganisms. (Other functions include removal of minerals, hydrocarbons, and volatile organic compounds, or VOCs). This destruction of microorganisms is usually accomplished by adding oxidizing agents such as chlorine, iodine and/or oxygen. In swimming pools and spas, the treatment of water to eliminate microorganism contamination ordinarily incorporates chemical treatment in combination with a mechanical filtering usually accomplished by drawing water from the pool with a pump, forcing it through a filter and returning it to the pool. Because the mere addition of a quantity of a chemical in liquid or soluble form permits the circulation system to effectuate quick dispersal, sanitization treatment is an easy task. Chlorine is typically used as a sanitation agent. However, chlorine is malodorous, rather inefficient, unhealthful, and not particularly economical.
At ordinary temperatures, chlorine is a gas, difficult to handle, and is not generally available. Accordingly, chlorine used in pools and ponds is combined with some compound that dissociates upon addition to pool water. Chlorine is popularly introduced as a constituent of calcium hypochlorite, sodium hypochlorite, chlorinated isocyanurates, or some other acid, or as a salt. If added as a salt, additional chemicals are required to avoid harmful accumulations of any other constituents of the salt, resulting in the problematic requirement of maintaining a chemical balance.
The process of purification of pool water using electrolysis has already been developed, and is well known in the art. Shindell, in U.S. Pat. No. 4,328,084 (1982) describes a water purification system employing salt in quantities sufficient to make the water slightly conductive and circulating that water through the electric field between a pair of dissimilar metal plates in order to dissociate salt ions from the water. The dissociated ions of salt and water are converted to oxidizing agents capable of destroying organic matter, which is converted to substances that can be removed by mechanical filtration. The process reportedly results in economical and effective purification. However, a major problem arises when a purification cell is placed in the circulation piping. The pump must operate continuously to maintain an effective level of chlorine or oligodynamic ions. This is not a problem in large commercial pools, however, in residential pools, the cost of continued operation becomes prohibitive. Also, governmental restrictions apply and costs of installation are high.
Metallic ions are known to kill or control algae and bacteria. It is well established that silver and copper ions are effective bactericides and algaecides. Treatment with silver has been used by NASA to purify water on the Apollo space missions. The practice of using silver and copper vessels to improve water quality dates back to ancient times. Ancient Phoenicians stored wine in silver urns to preserve it, providing one the earliest recorded examples of use of this metal for that purpose. Zinc, aluminum, and gold ions are just a few additional metals that can be used similarly.
Dahlegren, U.S. Pat. No. 4,337,136, (1982), purifies pool water by using a pair of silver-copper alloy electrodes extending from a floating container. Electrical energy is provided by a battery, using a timer switch that reverses the current as required to reduce erosion of the electrodes. The operating life of such a cell is limited by the requirement of batteries.
Sherman, in U.S. Pat. No. 5,085,753, describes a water purifier with a buoyant housing for supporting a purification cell below the water""s surface and for supporting a solar cell array for providing power for the purification cell. The cell operation includes electrolytic processes, electrocution and oxidation to destroy bacteria and algae.
There are two types of undesirable elements in pool water: 1) impurities in suspension, in the form of precipitates or colloids, and 2) dissolved, extremely small, electrically charged impurities in the ionic state. To eliminate these impurities, flocculation processesxe2x80x94consisting of introducing a reactant into the water to create colloids with adsorption propertiesxe2x80x94have been used. The colloids cause flocculation, which encloses the impurities in suspension. Large particles are formed and are separated from the water by filtering. To facilitate flocculation, the pH of the water has to be adjusted, in many cases, to below 7.4 or above 8.5.
2.2. Water Purification with Metal Ions
Conventional metal ion water purification devices use either (i) an excess of anodic reaction products, (ii) a particular linear relationship between purification cell current and treated water temperature, (iii) addition of sodium persulfate to water in which copper and silver ions have been added from copper-silver electrodes immersed in the water, or (iv) addition of salt in sufficient quantities to make the water slightly conductive followed by circulating the slightly conductive water through an electric field between a pair of electrode plates. These conventional devices and methods have generally been uneconomical and inefficient, and have focused on producing and regulating a DC current from an AC power source so as to maintain the safety of swimmers. The equipment is expensive, complicated and generally requires special installation and monitoring, thereby increasing manufacturing, operating and liability insurance costs.
Solar powered purification cells can overcome some of these problems, However, other drawbacks such as excessive gassing, corrosion, and accumulation of scale and deposits at the purification cell electrodes, result in reduced efficiency, destruction of the cell and/or the necessity of repetitively cleaning the electrodes.
In U.S. Pat. No. 5,279,748, issued to Hackett, water is passed through an xe2x80x9celectrolytic filterxe2x80x9d consisting of packed granules of copper and zinc, or xe2x80x9ca copper-zinc filter media.xe2x80x9d xe2x80x9cAs water passes through the electrolytic granules, a chemical reaction causes metal hydroxides to form in controlled amounts. These controlled releases of oxides are carried into the [previously and otherwise] filtered water where they kill bacteria and provide a hostile environment for algae and fungus growth.xe2x80x9d The amount of ionized metal entering the pool is controlled by varying the flow rate of water entering the electrolytic filter independent of the physical straining filter. The electrolytic filter is impervious to the bacterial growth to which similar filters (composed of other materials) can be susceptible. Hackett""s device is claimed to eliminate the need for chlorine.
U.S. Pat. No. 4,492,618 to Eder discloses a method in which electrodes of a copper-silver alloy are dissolved in the treated water via the application of a periodically reversed direct current. The electrically induced dissolution of the electrodes liberates copper and silver ions into the water. Sodium persulfate is added to the water for the xe2x80x9coxidation of organic matter.xe2x80x9d
In U.S. Pat. No. 4,608,247 issued to Heinig, silver is deposited on a large surface area support and combined with carbon to produce a composition favorable to the dissolution of silver ions in water.
In U.S. Pat. No. 5,352,369, also issued to Heinig, a method is described in which silver deposited on a large surface area alumina matrix acts as a catalyst xe2x80x9cin the presence of oxygen to form an active oxidizer in the water.xe2x80x9d This active oxidizer is claimed to be effective in the containment of bacterial and algal growth.
LeMire, in U.S. Pat. No. 4,935,116, describes a device consisting of concentric cylinders of dissimilar metals (copper and silver) that are electrically connected, with provisions to pass water to be treated in the annulus of said cylinders. The dissimilar metals form a voltaic cell whereby the metals are eroded to supply copper and silver ions to the water.
Finally, the preferred method and device for emitting metal ions in the method and system of the present invention is shown in predecessor U.S. patent application Ser. No. 09/237,553 filed on Jan. 26, 1999, for an APPARATUS AND METHOD FOR PURIFYING WATER WITH AN IMMERSED GALVANIC CELL, which patent application issued as U.S. Pat. No. 6,287,450 on Sep. 11, 2001. The contents of this predecessor patent incorporated herein by reference.
2.3. Silver-Based Water Purification
Silver-based water purification systems offer the most reliable and cost-effective alternatives to chlorine, a chemical that is increasingly criticized for the carcinogenic byproducts it leaves in water. Because of increasing pollution, utilities are forced to put far more chlorine into the supply chain. Recently, chlorine has been shown to produce by-products linked to cancer in laboratory animals, prompting an immediate US government review. These same byproducts have been generated by chlorination for a long time, but never in the quantities that are now being seen.
In Britain, silver ionization is being developed for mainstream water systems. Capitalizing on silver""s long-known biocidal properties and safety factors, the Institute of Water Ionization Technologies, UK, has developed silver ion generators for municipal water supplies. A recent project to study the control of Legionnaires disease by using silver ions was funded by the UK Department of the Environment. The disease is named after Legionella pneurnophilia, an organism that is widespread in small quantities within natural water sources. The bacteria is lethal at a water temperature of 95xc2x0 F., but can be killed at temperatures between 135 and 140xc2x0 F. Of the methods tested, silver/copper ions in soft water were found to be most effective. The copper ion disrupted the enzyme structures of the cell, allowing the silver ion to penetrate inside, where it rapidly inhibited the cell""s life support system.
U.S. regulations allow a silver level of 100 ppb in drinking water, but a silver level of only 20 ppb kills Legionella. A proposed European Union Drinking Water Standard has removed any upper limit for silver in drinking water, following the World Health Organization""s Guidelines for Drinking Wafer Quality, which determined that it is unnecessary to recommend any health-based guidelines for silver, as it is not hazardous to human health. Silver ion generators are currently being used in intensive care and heart transplant units of hospitals, and for poultry processing, engineering, brewing, cooling towers and swimming pools.
According to the most recent research on the swimming pool industry, published in 1993 by the National Spa and Pool Institute, 6.6 million individuals in the United States own pools, 3.4 million of which are in-ground and 3.2 million are aboveground. NSPI estimates that approximately 160,000 in-ground pools are built annually in the United States, in addition to about 475,000 aboveground pools. Silver-based mechanisms for keeping swimming pools sanitized are gaining widespread popularity among pool owners preoccupied with the mounting health hazards of chlorine.
Silver-copper ion systems have sanitized tens of thousands of swimming pools worldwide for several decades, inactivating organisms including Bacillus typhous, Legionella pneumophila and E. coli. Copper ions in the system have eliminated unwanted algae growth in pools, and have supplemented silver in controlling other pathogens, such as the polio virus. The technology works by producing positively charged ions that attack and destroy the negatively charged cells of organisms like bacteria and algae.
The purification method named the number one alternative to chlorine, based on research conducted by Swimming Pool and Spa Age magazine, is a silver catalyst system that has the capacity to instantly destroy bacteria and viruses. The system deposits silver microcrystals on the inside of a flow-through cartridge, which feeds oxygen into the water flow. The oxidized silver destroys bacteria, viruses and organic matter. Tests performed by the U.S. Environmental Protection Agency (EPA) at the University of Arizona, for example, found that the cartridge reduced the presence of E. coli in water by 99.96 percent within five seconds.
The use of silver in swimming pool sanitation is growing because of the many other advantages these systems offer. Silver systems are less expensive operationally than chlorine and other chemical systems. Also, silver does not evaporate from the water leaving the pool unprotected and does not stain the skin or bleach clothing.
2.4 Galvanic Cells
The predecessor U.S. patent application Ser. No. 09/237,553 filed on Jan. 26, 1999, for an APPARATUS AND METHOD FOR PURIFYING WATER WITH AN IMMERSED GALVANIC CELL shows a preferred means for liberating metal, specifically silver, ions during water treatment.
It is known by chemists and by practitioners of the water purification arts that each metal has its own electrochemical potential. Additionally, it is known that when two dissimilar metals, each with different electrochemical potentials are immersed in a conductive solution and electrically connected together, a galvanic cell or battery will be formed; such that current will flow from the metal of lower electrochemical (anode) potential to the metal of high chemical potential (cathode). Moreover, it is known that the metal of lower electrochemical potential will be dissolved into the electrolyte at a rate proportional to the current flowing between the two electrodes. This process transpires when a strip of a metal such as silver is immersed in water containing ionic species. A strip of another metal, such as platinum, is immersed in the water and is electrically connected to the silver strip, commonly by wire via an ampere meter. Current flows from the silver strip through the wire and ampere meter to the platinum strip due to the potential difference between the two metals. At the surface of the silver strip metallic silver atoms lose electrons to form silver ions. The electrons liberated by the oxidation of metallic silver flow through the electrical connection between the two metals, comprising a current which can be detected by the ampere meter. At the surface of the platinum electrons typically react with oxidizing species, such as hypochlorite ions.
A galvanic cell is a simple and effective means of introducing small quantities of beneficial metal ions into water. What has been misunderstood by previous investigators (LeMire and Hackett) is that the metal of higher electrochemical potential is cathodically protected by the flow of current in the galvanic cell and is therefore inhibited from dissolving. In fact, this effect is exploited in galvanized steel and in other applications such as the use of a sacrificial zinc electrode for underground tank and marine applications. Therefore, the devices described by LeMire and Hackett will only be effective in dissolving the metal of lower chemical potential. Silver, which has a relatively high electrochemical potential, will not be appreciably dissolved.
The present invention is based on the discovery that the operationally effective amount of a chemical oxidizing agent(s), normally chlorine, used to preclude microbial activity in the water of a pool, spa, or the like can be reduced, normally by a factor of at least two times (xc3x972) and more commonly from three to four times (xc3x973-xc3x974) by combination with an economic small amount of metal ions, normally silver. An algaecide (such as chelated copper) and/or a phosphate-removing compound (such as No Phos made by Natural Chemistry of Stamford, Conn.) is also strongly preferably present for maximally effective treatment using but minimal quantities of, in particular, the chemical oxidizing agent (the chlorine).
The present invention is also based on the further discovery that following a reduction in the concentration of a chemical oxidizing agent(s), normally chlorine, below an operationally effective level, economic small amounts of metal ions, normally silver, greatly increase the period of time elapsing before microbial growth increases, normally by about 48 hours (2 days) for a typical pool, spa or the like. This time elapsing before the water within the pool or spa becomes so greatly contaminated that recovery is difficult, requiring copious chemicals, can be extended when the normal treatment with and by the chemical oxidizing agent(s) (the chlorine) is, both at a time before interruption of this treatment and continuing after interruption, supplemented with an economically small and roughly steady infusion of metal ions, normally silver ions. The combination water treatment using both (i) a chemical oxidizing agent(s), normally chlorine, and (ii) metal ions, preferably silver ions, is also preferably accompanied by (iii) an algaecide such as chelated copper and/or (iv) a phosphate-removing compound. The combination is synergistic in prolongation of the period in which the treated water is protected against an avalanche of microbial growth when further addition of any one treatment agent, most normally and particularly the oxidizing agent (the chlorine), ceases.
Notably, prolongation of the period during which microbial growth is precluded if, for example, the pool or spa runs out of chemical oxidizing agent (chlorine), potentially savesxe2x80x94if the oxidizing agent is timely restored (i.e., within 48 hours)xe2x80x94a great deal of the chemical oxidizing agent, and much more than such amount as would simply make up for arrearage in application of the chemical oxidizing agent. This is because once microbial growth spikes due to inadequate water treatment, then extraordinary amounts of chemical oxidizing agent(s) and/or other chemicals and treatments are thereafter required to bring the growth under control, and to restore the treated water to satisfactory condition. Although it is far superior to keep the water of a pool, spa or the like constantly treated with microbial growth controlled, this is difficult with such constant monitoring and intervention as proves difficult for amateurs who may neglect or be absent from their pools and spas. It is very useful to any person attending to the maintenance of the pool or spaxe2x80x94and particularly to a non-professional maintainer such as, for example, a homeownerxe2x80x94to have the period extended in which action may permissively be taken, in response to measurement of insufficient pool or spa chlorine concentration, to restore adequate chlorine levels.
It should further be understood that reduction in the level of chemical oxidizing agent(s), normally chlorine, required for effective treatment of water in a pool or spa is highly desirable not only on economic and environmental grounds, but so that irritation of the eyes, skin and mucous membranes of bathers may be reduced. The reduction in the required effective level of chemical oxidizing agent(s), normally chlorine, achieved by the present invention is very dramatic: the (treated) waters of a pool or spa become like as a clean river, with the smells and irritation for which swimming pools are renown being greatly abated or even totally absent.
1. Theory of the Invention
An inventor cannot be held to positively know the theory of his invention, it being sufficient to demonstratively show that the invention works to realize a useful effect. Moreover, and despite an extensive search of the literature, the operative effect of metal ions in the preclusion of microbial growth is poorly understood.
However, it is hypothesized that a measurable synergism is occurring in the water treatment method of the present invention from a combined use of (i) a chemical oxidizing agent (s), normally chlorine, and (ii) metal ions, normally silver, including with the further optional, but preferred, addition of (iii) an algaecide, and/or (iv) a phosphate-removing compound. The method of the present invention for the treatment of the water in pools and spas and the like is perceived to be synergistic because each treatment element is most effectively doing something slightly different.
The oxidizing agent (s), normally chlorine, is perceived not only to oxidize microorganisms directly, but also to oxidize organic contaminants in the water, removing these organic contaminants and thereby robbing microorganisms including both bacteria and algae of their food source. Clearly when the oxidizing agent(s) is (are) completely consumed, and are no longer present, then the organic contamination level of the water rises unobstructed.
Regardless of how metal ions actually work to impair the growth of microbial organisms, no one appears to think that this is because the metal ions oxidize the organic food sources of the microorganism. The metal ions are far too few, and too sparse, to operate by this route. It is more likely that they somehow interfere with the normal development and/or life processes, potentially including reproduction, of microorganisms, notably bacteria. (Certain theories judged credible by the inventor find that metal ions interfere with membrane wall of the bacteria. Perhaps it should also be contemplated that metal ions, when added to microbe-containing solutions, show themselves not to be xe2x80x9cinstant killersxe2x80x9d, but need some xe2x80x9ccontactxe2x80x9d time to do their work.) It is difficult to treat water with significant organic nutrients by use of metal ions alone; life is difficult to suppress where abundant food exists, and whatever prophylactic effect metal ions have can be overwhelmed in a pool or spa that is laden with organic nutrients. Indeed, if organic contamination is sufficiently large, then the presence of even quite large amounts of metal ions is difficult, or even impossible, to detect in the measurement of microbial growth.
Putting these reasonably hypothesized characteristics of (i) oxidizing agents and (ii) metal ions together gives a colorably reasonable theory of the operation of the present invention. The oxidizing agent(s) oxidizes organic contamination in the water, robbing opportunistic microorganisms of any food source, for so long as the oxidizing agent(s) are present. When the oxidizing agent is consumed, then organic contamination commences to rise, and microbial life attempts to take hold. With the food supply still modest, this microbial life can multiply but slowly, which provides adequate time for interference with the growth/development and/or reproduction of the microbial life by any metal ions that are present. The metal ions (in reasonable concentration) thus xe2x80x9chold offxe2x80x9d such a xe2x80x9ccascadexe2x80x9d into microbial contamination as will, if the organic levels keep building, ultimately inevitably transpire. The metal ions would be expected to delay an xe2x80x9cexplosionxe2x80x9d in the abundance of microbial life, but not permanently prevent it; and this is exactly what is observed.
In this context the effect of any presence of an algaecide and/or a phosphate-removing compound, strongly preferred in the present invention, can also be hypothesized. The silver and zinc ions are better at interfering with the growth and/or reproduction of bacteria than of algae. A low level of algaecide keeps algae from commencing untrammeled growth and reproduction as soon as a food source (and light) becomes present. The phosphate-removing compound deals with a particular componentxe2x80x94phosphatexe2x80x94of the microorganisms"" food supply, and delays and obstructs the growth of microorganisms by depriving them of this essential element.
2. A Method of Treating the Water of a Pool or Spa
Accordingly, in one of its aspects the present invention is embodied in a method of treating the water of a pool or spa receiving ongoing organic contamination.
The method consists of introducing at predetermined rate each of (i) a chemical oxidizing agent, and (ii) metal ions.
An amount of (i) the chemical oxidizing agent introduced into the water is insufficient to inhibit the growth of bacteria without the presence of (ii) the metal ions. However, the same amount is perpetually sufficient to inhibit the growth of bacteria in continuing presence of (ii) the metal ions.
Meanwhile an amount of (ii) the metal ions introduced into the water is sufficient to temporarily inhibit the growth of bacteria should introducing of the chemical oxidizing agent cease, and after such time as previously introduced chemical oxidizing agent is effectively completely consumed. However, the metal ions are then so effective only for a period of time, which period is at least twice as long as would otherwise be the case should the metal ions have never been present. The period is not perpetual, bacteria ultimately growing in absence of the chemical oxidizing agent despite the continuing introduction and the continuing presence of the metal ions.
Thus the concept of the invention is this: (i) the chemical oxidizing agent, and (ii) the metal ions are each present in the treated water in such effective amounts as will permit that (ii) the metal ions, when and while still persisting (as is normal) in the treated water, will extend by at least two times the period in which growth of bacteriaxe2x80x94which will inevitably occurxe2x80x94will be inhibited if and when the introduction, and the persistence, of (i) the chemical oxidizing agent ceases.
Indeed, the introducing of (ii) the metal ions into the water is preferably sufficient to inhibit the growth of bacteria for at least twenty four hours, and more commonly forty-eight hours, after introducing of the chemical oxidizing agent ceases, and after a time when previously introduced chemical oxidizing agent is effectively completely consumed. This twenty four or forty-eight hour period is at least twice as long as would otherwise be the case should the metal ions have never been present. The exact quantity of metal ions introduced is a function of the volume of water treated, and the rate of its organic contamination. However, this specification disclosure will show metal-ion-producing galvanic cells, including as are packaged with dispensers of oxidizing agent (e.g., chlorine), that are broadly suitable to treat common private residential pools and spas to this standard.
The introducing may still further, preferably, be of (iii) an algaecide and/or (iv) a phosphate-removing compound. The amount of (iii) the algaecide introduced into the water is sufficient to inhibit the growth of algae should introducing of the chemical oxidizing agent cease, and after such time as previously introduced chemical oxidizing agent is effectively completely consumed. The amount of (iv) the phosphate-removing compound introduced into the water is also sufficient to inhibit the growth of algae should introducing of the chemical oxidizing agent cease, and after such time as previously introduced chemical oxidizing agent is effectively completely consumed. However, each substance is then so effective only for a period of time: which period is, however, usefully longer than would otherwise be the case should the substance have never been present. The period is, however, not perpetual; algae and/or bacteria ultimately growing in absence of the chemical oxidizing agent despite continuing introducing and continuing presence of any and all of (ii) the metal ions, (iii) the algaecide and/or (iv) the phosphate-removing compound.
In the preferred water treatment method the introducing is of metal ions preferably consisting essentially of silver and copper and zinc, and more preferably silver.
These silver metal ions are preferably derived from a galvanic cell having (i) a first metal drawn from the group of silver and copper and zinc, in physical and electrical contact with (ii) a second metal having a higher electrochemical potential than does the first metal, both metals being immersed in the water rendered electrically conductive by the presence of ions.
In the preferred galvanic cell at least one of the first metal and the second metal is in the form a planar mesh while the other metal is in a planar form laid flat against the mesh. By this construction openings within the at least one metal mesh permit circulation of water so that ions may readily come into contact with both the first and the second metals where there is little distance between them. Meanwhile, an effective amount of the first metal is liberated into the water so as to inhibit the growth of bacteria, fungi and algae by galvanic action
When the introducing is of silver metal ions, as is preferred, then the second metal of the galvanic cell preferably consisting essentially of a metal of the platinum group.
In the preferred water treatment method the introduced chemical oxidizing agent is preferably drawn from the group consisting essentially of chlorine and/or bromine. The most preferred oxidizing agent is sodium dichlor-S-triazinetrione dihydrate sufficient in quantity so as to produce a chlorine ion concentration of 0.2 to 1.0 ppm. Equivalent concentration of bromine ions is from 2-4 ppm. In either case the concentration is low by past standards: pools and the like are normally maintained at from 1-3 ppm chlorine ion concentration.
The preferred introducing of silver metal ions preferably derived from the galvanic cell is into chlorinated/brominated water rendered electrically conductive by the presence of chlorine and/or bromine ions. The amount of silver ions present, and the rate of silver consumption, will depend on the size of this galvanic cell, and the concentration of chlorine and/or bromine ions. For treatment of 100,000 gallons water it is normally preferred to use a galvanic cell having a silver matrix of with an apparent total two-sided area of the major surfaces of its foil electrodes on the order of 12.5-200 cm2. The xe2x80x9capparentxe2x80x9d area of these foil surfaces is not the actual total area because the surfaces may be perforated and/or possessed of substantial roughness. However, the basis of the measurement is clear enough: it is simply the two-sided area of the foils. A generally preferred galvanic cell consists of a 5 cm by 7 cm palladium coated perforated steel rectangle acting as support for four 2.5 cm. by 5 cm. silver leaf rectangles enclosed in a flat nylon mesh (thus having a total two-sided foil area of 4 foilsxc3x97(2.5 cm.xc3x975 cm.)/foilxc3x972 sides=100 cm2). The foils do not occupy much room, and are generally used until any silver component thereof is totally consumed.
The introducing of the chemical oxidizing agent preferably transpires by dissolving a water soluble solid form of oxidizing agent.
The introducing of the chemical oxidizing agent may transpire upstream in the circulating water of the pool or spa from the introducing of the metal ions to promote dissolution of the metal ions.
The introduced algaecide preferably consists essentially of chelated copper and/or compounds of chelated copper. These substances are preferably present, if at all, in only the minimal amounts recommended for pool and spa application by the manufacturer.
The introduced phosphate-removing compound is preferably the No Phos product of Natural Chemistry, Inc. This product is essentially lanthanum carbonate. The preferred quantity for use in 10,000 gallons water in accordance with the present invention is from 1-15 oz. monthly. Just as with the concentration of oxidizing agent, the concentration is low by the manufacturers recommendations: pools and the like are recommended to be dosed with either 16, 32, or 48 oz. No Phos as will generally realize about 300-600; 600-900; or  greater than 900 ppm phosphate ion level in 10,000 gallons water.
The chemical oxidizing agent, the metal ions, the algaecide and the phosphate-removing compound may be introduced from physically separate devices each within the circulating water of the pool or spa, or from separate chambers of a single, monolithic and integrated, device.
Accordingly, just as with previous treatment of the water of pools and spas, there is no hard and fast rule, no chemical formula, that says to use from 1-3 parts of substance A, from 2-7 parts of substance B, and so on. Rather, a practitioner of the water control arts will recognize that adjustment of treatment elements, and their concentrations, is a function of the water, and the water purification task, at hand. It is, however, easy to recognize the synergism of the present invention. Literally every treatment chemical, with the possible exception of a chelated copper algaecide if such be present, is present at levels far below recommended effective levels, and sometimes below levels at which any effectiveness at all would be predicted to be had in the prior art. It is especially important that the oxidizing agent, normally chlorine, is used in water treatment at record low levels: the hallmark of the present invention.
3. A Water Treatment Device
In another of its aspects the present invention is embodied in a replaceable consumable device insertable in a recirculation flow path of a pool or a spa, including insertable in a fixed housing plumbed into the recirculation system of a pool or spa or insertable in a dispenser that floats in the pool or spa, for treating the water of the pool or the spa when the pool or spa receives ongoing organic contamination.
The preferred device minimally includes (i) a first dispenser for introducing at predetermined rate a chemical oxidizing agent, and (ii) a second dispenser for introducing at predetermined rate metal ions.
The amount of the chemical oxidizing agent introduced into the water by (i) the first dispenser is insufficient to inhibit the growth of bacteria without the presence of the metal ions, but is perpetually sufficient to inhibit the growth of bacteria in continuing presence of the metal ions as are introduced by (ii) the second dispenser.
Meanwhile, the amount of the metal ions introduced into the water by (ii) the second dispenser is sufficient to inhibit the growth of bacteria should introducing of the chemical oxidizing agent by (i) the first dispenser cease, and even after such time as previously introduced chemical oxidizing agent is effectively completely consumed. However, it is then so effective only for a period of time, which period is at least twice as long as would otherwise be the case should the metal ions have never been present. This extension period is, however, not perpetual; bacteria will ultimately grow in absence of the chemical oxidizing agent despite the continuing introducing and the continuing presence of the metal ions.
In the preferred water treatment device the introducing of the metal ions into the water by (ii) the second dispenser is sufficient to inhibit the growth of bacteria for at least twenty four hours after introducing of the chemical oxidizing agent by (i) the first dispenser ceases, and even after a time when previously introduced chemical oxidizing agent is effectively completely consumed. This twenty four hour period at least twice as long as would otherwise be the case should the metal ions have never been present.
The most preferred water treatment device further includes (iii) a third dispenser for further introducing an algaecide and/or a phosphate-removing compound, or even a (iv) a fourth dispenser for further introducing the remaining one of the algaecide and/or the phosphate-removing compound. The amount of the algaecide, and/or the phosphate-removing compound introduced into the water by this (these) optimal third (and fourth) dispenser(s) is sufficient to inhibit the growth of algae should introducing of the chemical oxidizing agent by the first dispenser cease, and even after such time as previously introduced chemical oxidizing agent is effectively completely consumed. However, it is then so effective only for a period of time, which period is longer than would otherwise be the case should the algaecide and/or the phosphate-removing compound have never been present. However, the extension period is not perpetual; algae ultimately growing in absence of the chemical oxidizing agent despite continuing introducing of the metal ions by (ii) the second dispenser.
In the most preferred water treatment device (i) the first dispenser is preferably but a solid form of water soluble chemical oxidizing agent dissolving over time to introduce chemical oxidizing agent into the water.
The preferred (ii) second dispenser is, however, considerably more complex. A galvanic cell having (i) a first metal drawn from the group of silver and copper and zinc, in physical and electrical contact with (ii) a second metal having a higher electrochemical potential than does the first metal, immersed in the recirculating water rendered electrically conductive by the presence of ions, dispenses ions of the first metal.
The optional (iii) third and (iv) fourth dispensers are simple chambers which, however, hold and dispense chemicals that are in amount and dispensing rate strictly in accordance with the combinatorial principles of the present invention where synergism is promoted through balance, and coaction.
4. An Integrally Packaged Water Treatment System
In another of its aspects the present invention is embodied in an integrally packaged water treatment system particularly for use in the flow of recirculating water of a pool or spa.
The preferred water purification system includes (i) a permanent housing with refillable containers containing (ii) a consumable water soluble chemical oxidizing agent, and (iii) a consumable galvanic cell producing metal ions. The (ii) oxidizing agent and (iii) galvanic cell are optionally prepackaged separately or together in a disposable cartridge (s) insertable into and easily removed from the permanent housing. Contrary to previous alliqots of pool chemicals and the like, the chemical oxidizing agent is preferably present in the system in an amount that is intentionally consumed at a time before the galvanic cell is consumed.
The most preferred water purification system further contains an algaecide and/or a phosphate-removing compound, preferably both. In this case the amount of chemical oxidizing agent present is also intentionally consumed before either the algaecide or the phosphate-removing compound (whichever is present) is consumed. Each of the algaecide and/or phosphate-removing compound may also be prepackaged in a disposable cartridge insertable into and easily removed from the (i) permanent housing.
The chemical oxidizing agent preferably consists of a solid form dissolving over time to introduce chemical oxidizing agent into the water.
The galvanic cell preferably includes (i) a first metal drawn from the group of silver and copper and zinc, in physical and electrical contact with (i) a second metal having a higher electrochemical potential than does the first metal, immersed in the recirculating water rendered electrically conductive by the presence of ions.
The algaecide or the phosphate-removing compound (whichever is present) are present in slow-release form, being water purification does not principally rely on these elements, but rather primarily relies on the chemical oxidizing agent and secondarily relies on the metal ions.
These and other aspects and attributes of the present inventionxe2x80x94including the nominal quantities and concentrations (which are separate things) of the system components typically delivered into service for typical pools and the likexe2x80x94will become increasingly clear upon reference to the following drawings and accompanying specification.